The present invention relates to a locking device, and more particularly to a locking device for a ratchet wheel.
The locking device for a ratchet wheel disclosed previously by this inventor in Taiwanese Patent 79213029 is provided with a sector braking member, which has a serrated top portion and is coupled with a rotor fitted over with a protective shell provided with a toothed ring. The rotor is locked in place at the time when the serrated top portion of the sector braking member meshes with the toothed ring of the protective shell of the rotor. In addition, the braking member is coupled with a lock core of locking means by means of a clutching mechanism made up of a pair of bevel wheels and a spring disposed between the two bevel wheels. Therefore, the effectiveness of braking on the rotor by the braking member can be controlled by the unlocking and the locking actions of the locking device.
According to the manufacturing experience of this inventor, the locking device described above is defective in design in that the disengagement of the serrated portion of braking member from the toothed ring of the protective shell of rotor does not take place easily. In other words, it is often difficult to have the locking device shifted from a locking state to an unlocking state. Furthermore, the two bevel wheels fail to engage at times, thereby resulting in a failure of the lock core to actuate the braking member synchronously.